1. ABCD An essential amino acid, D, is made from precursors A, B, and C by the following pathway: Several mutant bacteria are isolated that are unable to grow on minimal media. Each is tested on minimal media, as well as on minimal media plus chemicals A, B, C and D. Strain Complete Media Minimal Media + A Minimal Media + B Minimal Media + C Minimal Media + D Wild typeY N YYYY Mutant 1Y N NNNY Mutant 2Y N NYYY Mutant 3Y N NNNN Mutant 4Y N NNYY Q1: Mutant 1 has lost the function of the gene encoding the enzyme required for the reaction of: A)A to B B)B to C C)C to D D)None of the above

2. ABCD An essential amino acid, D, is made from precursors A, B, and C by the following pathway: Several mutant bacteria are isolated that are unable to grow on minimal media. Each is tested on minimal media, as well as on minimal media plus chemicals A, B, C and D. Strain Complete Media Minimal Media + A Minimal Media + B Minimal Media + C Minimal Media + D Wild typeY N YYYY Mutant 1Y N NNNY Mutant 2Y N NYYY Mutant 3Y N NNNN Mutant 4Y N NNYY Q2: Mutant 2 has lost the function of the gene encoding the enzyme required for the reaction of: A)A to B B)B to C C)C to D D)None of the above

3. ABCD An essential amino acid, D, is made from precursors A, B, and C by the following pathway: Several mutant bacteria are isolated that are unable to grow on minimal media. Each is tested on minimal media, as well as on minimal media plus chemicals A, B, C and D. Strain Complete Media Minimal Media + A Minimal Media + B Minimal Media + C Minimal Media + D Wild typeY N YYYY Mutant 1Y N NNNY Mutant 2Y N NYYY Mutant 3Y N NNNN Mutant 4Y N NNYY Q3: Mutant 3 has lost the function of the gene encoding the enzyme required for the reaction of: A)A to B B)B to C C)C to D D)None of the above

4. ABCD An essential amino acid, D, is made from precursors A, B, and C by the following pathway: Several mutant bacteria are isolated that are unable to grow on minimal media. Each is tested on minimal media, as well as on minimal media plus chemicals A, B, C and D. Strain Complete Media Minimal Media + A Minimal Media + B Minimal Media + C Minimal Media + D Wild typeY N YYYY Mutant 1Y N NNNY Mutant 2Y N NYYY Mutant 3Y N NNNN Mutant 4Y N NNYY Q4: Mutant 4 has lost the function of the gene encoding the enzyme required for the reaction of: A)A to B B)B to C C)C to D D)None of the above